OP0223 THE EFFECT OF ANTIMALARIALS ON THE RISK AND SEVERITY OF BACTERIAL, VIRAL, FUNGAL AND SYSTEMIC-SPECIFIC INFECTIONS IN RHEUMATOID ARTHRITIS
Authors: M. Bredemeier, M. Campos, F. Della, A. Duarte, M. Pinheiro, B. Stadler, J. C. Macieira, R. Ranza, J. Miranda, V. Valim, G. Castro, M. Bertolo, M. D. F. Sauma, V. Fernandes, A. C. Medeiros-Ribeiro, R. Botelho, C. Brenol, H. M. Da Silveira DE Carvalho, S. Studart, G. Da Rocha Castelar Pinheiro, L. Rocha, H. De Leon de Lima, I. Pereira, M. Ohira Gazzeta, A. Kakehasi, P. Louzada, A. L. S. Hayata, F. Pina, C. Lupo, L. Balarini, I. G. Silveira, S. Kowalski, D. Titton, A. Ranzolin, R. Xavier, I. Laurindo, M. Antonio Araujo Da Rocha Loures
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Antimalarials (AM) have been related to a lower risk and severity of infections in systemic lupus erythematosus [1], but in rheumatoid arthritis (RA) the results are not unanimously favorable to a possible protective effect exerted by AM [2,3]. In our recent study of RA patients treated with biologic disease modifying anti-rheumatic drugs (bDMARDs) or JAK inhibitors (JAKi), a secondary analysis suggested lower risk of total (25% reduction) and serious infections (47% reduction) with concomitant use of AM [4]. <h3>Objectives</h3> To evaluate the association of the use of AM with the risk of total and serious bacterial, viral, fungal and system-specific infections in RA patients treated with conventional synthetic DMARDs (csDMARDs) and/or bDMARDs/JAKi. <h3>Methods</h3> BiobadaBrasil is a multicentric registry-based cohort study of Brazilian patients with rheumatic diseases starting a new csDMARD or their first bDMARD or JAKi [5]. The present analysis includes RA patients recruited from Jan 2009 to Oct 2019, followed-up over one or multiple (up to six) courses of treatment (latest date, Nov 19, 2019) with csDMARDs and/or bDMARDs/JAKi. A treatment course is defined as a period during which the medication scheme of does not change, except for dose adjustments. The primary outcome was the incidence of total infections (SIs) caused by bacteria, viruses and fungi (analyzed separately). The microbiologic etiologic agent was defined by cultural exam or, alternatively, high clinical suspicion, but not all infection had a clearly defined etiology (these ones were excluded from the analysis by etiologic agent). Serious infections according to type of microorganism and system-specific infections served as secondary outcomes. Negative binomial regression with generalized estimating equations (to calculate the incidence rate ratios [ÌRRs]) and extended (frailty) multivariate Cox proportional hazards models were used for statistical analyses (both types of analyses including time- fixed and time-varying covariates over multiple courses of treatment to adjust for confounding). <h3>Results</h3> In total, 1671 patients (2891 treatment courses, 8944.1 patient-years [PY]; most treatment courses [in total, 2335] including bDMARDs or JAKi) were enrolled. AM were used over 512 courses (2036.8 PY) of therapy. The overall incidence of infections caused by bacteria, fungi and viruses were 10.2, 1.9, 1.0/100 PY, respectively. The mIRRs for the primary and secondary outcomes are presented in the Figure 1. There were statistically significant reductions in the risk of serious and non-serious bacterial infections, as wells as serious lower respiratory tract infections, digestive tract infections and those affecting skin or mucosae. These effects were observed regardless of concomitant use or not of bDMARDs/JAKi or methotrexate by the patients. <h3>Conclusion</h3> Among RA patients followed-up in our cohort study, the use of antimalarials was associated with reduction in the risk of bacterial infections, especially serious ones, and there was protection against infections affecting the respiratory and digestive systems and skin/mucosae. <h3>References</h3> [1]Feldman CH et al. Arthritis Rheumatol 2015;67:1577-85.2. [2]Smitten AL et al. J Rheumatol 2008;35:387-93. [3]Kremer JM, et al. RMD Open 2020;6. [4]Bredemeier M, et al. Annals of the Rheumatic Diseases 2022;81:360-361.3. [5]Bredemeier M et al. J Rheumatol 2021;48:1519-27. <h3>Acknowledgements</h3> to Patricia Cabral -coordinator- and SBR. <h3>Disclosure of Interests</h3> None Declared.